Agrochemical formulations are designed to make the product practical in use and to obtain an evenly distribution of a small amount of active substance across a wide area for treatment of an agricultural crop. When developing a formulation, a number of factors need to be taken into account: the type of application, the crop to be treated, regional variation in agronomical practice, and last but not least physical-chemical properties of the active substance, including melting point, solubility and chemical stability.
Liquid formulations are preferred by the farmer for preparing spray solutions for several reasons. They can be measured volumetrically, are easy to handle, spontaneously form stable emulsions or dispersions and, given appropriate container design, are usually easy to rinse out of the packaging. They are also easy to handle in bulk handling systems and generally do not cause application problems.
An emulsifiable concentrate consists of an active ingredient dissolved in an organic solvent, with sufficient emulsifier added to create and oil-in-water emulsion after addition of water to the emulsifiable concentrate. An emulsion is a mixture in which one liquid is suspended in another liquid. In an agrochemical emulsion, water is often the continuous phase (carrier) while oil droplets consisting of solvent plus agrochemical active ingredient, are dispersed in it.
WO 2007/017501 discloses emulsifiable concentrate formulations comprising a pesticide active ingredient multicomponent solvent system and multicomponent emulsifying system. All examples comprise an aromatic hydrocarbon mixture.
The solvent for use in an emulsifiable concentrate is selected according to its capability of solubilizing a selected active ingredient. This requirement is often fulfilled by aromatic and isoparaffinic solvents. However, the use of solvents with low flash points is becoming increasingly restricted as governmental regulations are tightening their transportation and handling. Hence, there is a need to avoid the use of flammable solvents for the solubilization of active ingredient, especially for pesticidal active ingredients.
In order produce a concentrated emulsion, the emulsifier must be carefully selected to obtain a formulation in which a selected agrochemical active ingredient is optimally distributed. To form stable concentrated emulsions, irreversible anchoring in the oil droplet and strong steric repulsion between particles are required. Irreversible flocculation, or coalescence, of the emulsions is to be prevented by creating an energy barrier that is sufficient to prevent the droplets from approaching each other closely. Steric stabilization can be produced using surfactants.
The demanding requirements outlined above result in products being developed for a specific active ingredient. This results in a large range of products in storage at a formulation plant. Whereas product development for a new formulation takes a long period of time, demand for just-in-time delivery in response to the onset diseases plant is increasing. Formulators of agrochemicals are one the one hand faced with increasing costs for raw materials and storage space, and on the other hand with increasing complexity of agrochemical formulations.
EP 1625791 discloses a liquid insecticidal composition comprising a mixture of dimethyl sulfoxide, gamma-butyrolactone and a propylene oxide/ethylene oxide block copolymer surfactant in combination with a chloronicotinyl compound.
U.S. Pat. No. 4,502,861 discloses a mothproofing formulation for application to keratinous materials comprising cypermethrin, a barbituric acid, diethylene glycol ethyl ether, amine or amide surfactant, and a block copolymer of propylene glycol and ethylene oxide.
WO 2007/017501 discloses an emulsifiable concentrate comprising a phenylsimicarbazone, a solvent system, one or more emulsifiers and optionally further formulation additives for use against insect pests.
For none of the above formulations it was disclosed whether the solvent/surfactant pair is compatible with other active ingredients, in particular with a large number of diverse pesticidal active ingredients.
There remains a need in the art for improving the manufacturing process of agrochemical products and for emulsifiable pesticide solutions, in particular for products with an improved environmental profile, that are easy to manufacture, store and use, and are economically interesting to produce.
The present invention aims to resolve or ameliorate at least some of the problems mentioned above. In particular, the invention thereto aims to provide emulsifiable pesticide solutions that are capable of reducing warehouse costs whilst not restricting the formulator of providing farmers with a broad product range of emulsifiable concentrates. The emulsifiable concentrates are capable of providing good emulsion stability over an extended period at both elevated and freezing temperatures. In addition the agrochemical formulations have a lower environmental impact and are safer in use.